Tecovirimat Resistance in an Immunocompromised Patient With Mpox and Prolonged Viral Shedding
Authors: Helena Mertes, Antonio Mauro Rezende, Isabel Brosius, Reinout Naesens, Johan Michiels, Tessa deBlock, Jasmine Coppens, Christophe Van Dijck, Peter Bomans, Emmanuel Bottieau, Marjan Van Esbroeck, Kevin K. Ariën, Laurens Liesenborghs, Koen Vercauteren
Journal: Annals of Internal Medicine (2023)

LettersAugust 2023Tecovirimat Resistance in an Immunocompromised Patient With Mpox and Prolonged Viral SheddingFREEHelena Mertes, MD*, Antonio Mauro Rezende, MSc, PhD*, Isabel Brosius, MD*, Reinout Naesens, MD, Johan Michiels, BSc, Tessa deBlock, BSc, Jasmine Coppens, MSc, PhD, Christophe Van Dijck, MD, PhD, Peter Bomans, MD, Emmanuel Bottieau, MD, PhD, Marjan Van Esbroeck, MD, Kevin K. Ariën, MSc, PhD, Laurens Liesenborghs, MD, PhD†, Koen Vercauteren, MD, PhD†Helena Mertes, MD*Department of Internal Medicine and Infectious Diseases, Ziekenhuisnetwerk Antwerpen, Antwerp, Belgium, Antonio Mauro Rezende, MSc, PhD*Clinical Virology Unit, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Isabel Brosius, MD*Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Reinout Naesens, MDDepartment of Medical Microbiology and Infection Prevention & Control, Ziekenhuisnetwerk Antwerpen, Antwerp, Belgium, Johan Michiels, BScVirology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Tessa deBlock, BScClinical Virology Unit and Clinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Jasmine Coppens, MSc, PhDClinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Christophe Van Dijck, MD, PhDDepartment of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Peter Bomans, MDDepartment of Pneumology, Ziekenhuisnetwerk Antwerpen, Antwerp, Belgium, Emmanuel Bottieau, MD, PhDDepartment of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Marjan Van Esbroeck, MDClinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Kevin K. Ariën, MSc, PhDVirology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Laurens Liesenborghs, MD, PhD†Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, Koen Vercauteren, MD, PhD†Clinical Virology Unit and Clinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, BelgiumAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/L23-0131 SectionsAboutVisual AbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail Background: Tecovirimat, an inhibitor of the viral VP37 envelope-wrapping protein used to treat severe monkeypox virus (MPXV) infection, has a low barrier to resistance (1, 2). A tecovirimat-resistant MPXV variant was recently identified at the autopsy of an immunocompromised patient with mpox after prolonged tecovirimat treatment (3).Objective: To describe the rapid selection of a tecovirimat-resistant MPXV variant during treatment of a severely immunocompromised patient with prolonged MPXV infection.Case Report: A 53-year-old man who had been vaccinated for smallpox in childhood presented in November 2022 with weight loss; a longstanding large, painful anal ulcer; and proctitis, but without skin lesions. Work-up revealed HIV-1 infection with pronounced immunosuppression (plasma viral load, 523 000 copies/mL; CD4+ T-lymphocyte count, 0.02 × 109 cells/L), chronic hepatitis B virus infection, latent syphilis, Cryptococcus neoformans antigenemia, anal Chlamydia trachomatis infection, and cytomegalovirus infection.The initiation of antiretroviral therapy (ART) was deferred due to travel. Six weeks after the HIV diagnosis, the patient was admitted for worsening anal pain. Antiretroviral therapy (bictegravir, 50 mg; emtricitabine, 200 mg; and tenofovir alafenamide, 25 mg) and intravenous ganciclovir for suspected cytomegalovirus colitis were started. Perianal disease deteriorated, and necrotizing vesicles appeared on the neck and buttocks on days 15 and 20 of ART, respectively (in addition to cerebral toxoplasmosis). Mpox immune reconstitution inflammatory syndrome was suspected, and polymerase chain reaction testing of the different lesions, stored plasma samples, and anal biopsy specimens was performed. All tested positive for MPXV (Figure 1).Figure 1. Clinical and virologic evolution over time relative to the initiation of the 2 consecutive courses of tecovirimat.The 2 courses of tecovirimat are indicated as "1" and "2". Sequencing results (method as described in reference 5, using an R10.4.1 flow cell [Oxford Nanopore Technologies]) are represented as pie charts above the graph: The external ring of each pie represents the proportions of wild-type (N267 [WT]; green) and resistant (N267D [R]; orange) MPXV variant populations in anal lesion samples. Numbers above each pie indicate the percentage of the N267D (R) allele frequency (orange) and the total (N267D [R] and N267 [WT]) allele depth (black) (only considering bases with a minimum quality score [Phred score] of Q30). The evolution of Ct values of anal lesions (black circles) and blood samples (red circles), HIV VL (triangles), and CD4+ cell count (squares) are presented on the graph. Crosses indicate positive MPXV culture samples. The timing of the appearance and resolution of the anal ulcer and skin lesions is indicated by the red bars underneath the graph. To convert CD4+ cell counts to ×109/L, multiply by 0.001. ART = antiretroviral therapy; Ct = PCR cycle threshold; LOD = limit of detection; MPXV = monkeypox virus; PCR = polymerase chain reaction; R = resistant; VL = viral load; WT = wild-type. Consensus sequence National Center for Biotechnology Information GenBank accession numbers: d-87 02 Nov_2022_anal: OQ672570; d-9 19_Jan_2023_anal: OQ672571; d-2 26_Jan_2023_anal: OQ672572; d-2 26_Jan_2023_neck: OQ672573; d5 02_Feb_2023_anal: OQ672574; d5 02_Feb_2023_gluteal: OQ672575; d11 08_Feb_2023_anal: OQ672576; d16 13_Feb_2023_anal: OQ672577; d25 23_Feb_2023_anal: OQ672578; d31 28_Feb_2023_anal: OQ672579. Download figure Download PowerPoint Oral tecovirimat (600 mg twice daily) was started 1 day after the confirmation of MPXV infection (ART day 39). During the initial 2-week course, all lesions improved but anal lesion resolution was incomplete and viral shedding persisted. Tecovirimat treatment was extended for 2 weeks, after which the clinical evolution continued to be favorable. Daily intake was reliably reported throughout treatment. After 25 days of tecovirimat treatment, MPXV DNA became undetectable in blood. In contrast, except for a temporary decrease on day 11 of treatment (cycle threshold [Ct], 28.39), the anorectal viral load remained high up to day 48 (Ct, 21.58) and detectable up to the end of follow-up (Ct, 33.94 at day 88).Retrospective MPXV sequencing of the anorectal samples revealed a dominant variant population (at 94.11% allele frequency) carrying an F13L gene mutation (encoding an N267D variant of VP37) as early as 11 days after initiation of tecovirimat treatment (Figure 1). This variant was already detectable as a minor population before tecovirimat initiation in anorectal (3.41% at day −87 and 0.64% at day −2), neck (0.23% at day −2), and gluteal (0.05% at day −11) lesion samples. In vitro, this N267D mutation was associated with a 350-fold increase in the half maximal effective concentration of tecovirimat compared with wild-type (WT) virus (2103 nM for N267D vs. 5.9 nM for WT MPXV) (Figure 2) and with reduced viral outgrowth in a direct competition assay.Figure 2. In vitro drug susceptibility testing.MPXV was isolated from anal swab samples on days −2 and 31 by spinoculation on vero cells, and virus stock was prepared by double passaging on vero cells (for 3 and 4 days, respectively). Viral stocks were confirmed for the presence of WT and N267D mutant virus by whole-genome sequencing (i.e., 100% WT/0% R and 36% WT/64% R in viral stocks derived from day −2 and 31 samples; indicative of a comparative outgrowth disadvantage for the N267D mutant virus present at 98.34% in the patient sample at day 31). Serial dilutions of tecovirimat were incubated with 10 plaque-forming units (0.0005 multiplicity of infection) of dominant WT (green circles) and dominant N267D mutant virus (orange circles) containing viral stocks, on confluent vero cells for 4 days in 96 well plates in a plaque reduction assay. EC50 values were calculated using a 4-variable logistic model in GraphPad Prism v.9. Cmin = reported minimal concentration of tecovirimat (after 600-mg oral dose; from reference 1); EC50 = half maximal effective concentration; MPXV = monkeypox virus; R = resistant; WT = wild-type.* The proportion of viral growth (expressed in amount of plaques) compared with the untreated condition. Download figure Download PowerPoint Discussion: Our report confirms the potential rapid selection of resistant mutant virus during tecovirimat monotherapy, and we believe this report is the first to study this phenomenon longitudinally. A variant (VP37 N267D) with substantiated tecovirimat resistance was selected within the standard 2-week treatment.Although MPXV infections are mostly self-limiting, prolonged disease has been described in immunocompromised patients (4). Our patient had protracted viral shedding of at least 87 days before initiation of tecovirimat treatment, when a minor fraction of the resistant variant was already detectable. Indeed, intrahost viral evolution enhanced by prolonged replication may influence the viral population's diversity and subsequent ability to escape antiviral pressure. However, in the absence of pharmacokinetic and pharmacodynamic monitoring, we cannot rule out subtherapeutic tecovirimat levels due to factors such as insufficient high-fat food intake.Despite the emergence of tecovirimat resistance in our patient, the clinical evolution was favorable, possibly due to further immune reconstitution. Similar to other VP37 amino acid substitutions that confer resistance to tecovirimat in orthopox viruses (2), decreased viral fitness may play a role, as suggested by the in vitro outgrowth assay. Whether in vivo fitness is affected in the N267D variant described here remains to be determined.The rapid selection of resistance in our patient highlights the risks of tecovirimat monotherapy, especially in the context of prolonged disease and immunosuppression. In such cases, we advocate for surveillance for resistant variants, emphasis on immune reconstitution, monitoring of viral clearance, and strict adherence to infection prevention measures. Additional research is needed on strategies that increase the barrier to resistance, including the use of antiviral combination treatments.References1. U.S. Food and Drug Administration. FDA Application Review Files, Microbiology Review. 2018. Accessed at www.accessdata.fda.gov/drugsatfda_docs/nda/2018/208627Orig1s000MicroR.pdf on 27 March 2023. Google Scholar2. Duraffour S, Lorenzo MM, Zöller G, et al. ST-246 is a key antiviral to inhibit the viral F13L phospholipase, one of the essential proteins for orthopoxvirus wrapping. J Antimicrob Chemother. 2015;70:1367-1380. [PMID: 25630650] doi:10.1093/jac/dku545 CrossrefMedlineGoogle Scholar3. Alarcón J, Kim M, Terashita D, et al. An mpox-related death in the United States. N Engl J Med. 2023;388:1246-1247. [PMID: 36884032] doi:10.1056/NEJMc2214921 CrossrefMedlineGoogle Scholar4. Mitjà O, Alemany A, Marks M, et al; SHARE-NET writing group. Mpox in people with advanced HIV infection: a global case series. Lancet. 2023;401:939-949. [PMID: 36828001] doi:10.1016/S0140-6736(23)00273-8 CrossrefMedlineGoogle Scholar5. Berens-Riha N, De Block T, Rutgers J, et al. Severe mpox (formerly monkeypox) disease in five patients after recent vaccination with MVA-BN vaccine, Belgium, July to October 2022. Euro Surveill. 2022;27:2200894. [PMID: 36695462] doi:10.2807/1560-7917.ES.2022.27.48.2200894 CrossrefMedlineGoogle Scholar Comments0 CommentsSign In to Submit A Comment Author, Article, and Disclosure InformationAuthors: Helena Mertes, MD; Antonio Mauro Rezende, MSc, PhD; Isabel Brosius, MD; Reinout Naesens, MD; Johan Michiels, BSc; Tessa deBlock, BSc; Jasmine Coppens, MSc, PhD; Christophe Van Dijck, MD, PhD; Peter Bomans, MD; Emmanuel Bottieau, MD, PhD; Marjan Van Esbroeck, MD; Kevin K. Ariën, MSc, PhD; Laurens Liesenborghs, MD, PhD; Koen Vercauteren, MD, PhDAffiliations: Department of Internal Medicine and Infectious Diseases, Ziekenhuisnetwerk Antwerpen, Antwerp, BelgiumClinical Virology Unit, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, BelgiumDepartment of Clinical Sciences, Institute of Tropical Medicine, Antwerp, BelgiumDepartment of Medical Microbiology and Infection Prevention & Control, Ziekenhuisnetwerk Antwerpen, Antwerp, BelgiumVirology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, BelgiumClinical Virology Unit and Clinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, BelgiumClinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, BelgiumDepartment of Pneumology, Ziekenhuisnetwerk Antwerpen, Antwerp, BelgiumNote: This study was approved by the Ziekenhuis Netwerk Antwerpen Ethical Committee (number 009-OG031).Acknowledgment: The authors thank Kadrie Ramadan, Sandra Coppens, Fien Vanroye, and Jacob Verschueren for excellent technical and logistic support.Financial Support: This work was funded by the Department of Economy, Science, and Innovation of the Flemish government (K.V., K.A., and M.V.E.) and the Research Foundation–Flanders (grant G096222N; E.B. and L.L.). The funders had no role in the collection, analysis, or interpretation of data, nor in the writing of the report or the decision to submit the manuscript for publication.Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L23-0131.Corresponding Author: Koen Vercauteren, MD, PhD, Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium; e-mail, kvercauteren@itg.be.This article was published at Annals.org on 25 July 2023.* Drs. Mertes, Rezende, and Brosius contributed equally to the work.† Drs. Liesenborghs and Vercauteren contributed equally to the work. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics Current IssueAugust 2023Volume 176, Issue 8Page: 1141-1143KeywordsAntiretroviral therapyHIVLesionsMonkeypoxViral loadVirology ePublished: 25 July 2023 Issue Published: August 2023 Copyright & PermissionsCopyright © 2023 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...